The present invention relates generally to firearms and, in particular, to modifications made to standard semiautomatic breech-locked, recoil operated firearms for producing reliable, repetitive blank-fire capability in these pistols.
In many conventional semi-automatic weapons, including the "BROWNING" and "COLT/BROWNING" family of pistols, a breech-lock, recoil activated system is utilized where the barrel and slide are locked together for a predetermined distance in response to firing of a bullet to effect a complete firing cycle, i.e., the opening of the breech after firing a shot, the extraction and ejection of the empty cartridge shell, the cocking of the hammer, the presentation and introduction of a loaded cartridge to the barrel and the closing of the breech are automatically effected through the energy of recoil of the breech closing part. Since by nature breech-locked, recoil activated firearms rely upon the phenomenon of projectile motion within the barrel--which is derived from the projectile mass of the bullet--to create the recoil forces necessary to effect repetitive cycling of the mechanism, blank-fire in this class of firearm will not ordinarily impart the appropriate type or degree of force necessary to effect repetitive cycling of the mechanism. Even with the presence of a bore-restricting element to augment gas pressure and rearward gas thrust against the breech face, the type of force generated is qualitatively different from that evidenced in projectile-motivated live-fire conditions where the projectile's moment of inertia produces recoil characteristics that overcome the breech-locking impediment.
In an effort to overcome the breech-locking impediment so as to fire blank ammunition, the breech locking element in this type of firearm may be eliminated, in effect to create a blowback system of operation devoid of any breech-locking barrel interconnection in an attempt to bypass the problematic absence of forces in projectile-free blank ammunition. However, elimination of the breech-locking features manifests other difficulties in operation of the pistol such as cartridge ejection, cartridge feeding and slide return into battery.
U.S. Pat. No. 4,907,489 to Teague relates to a blank fire configuration for a recoil operated automatic pistol for converting a standard live-fire pistol to a blank-firing pistol. In accordance with the Teague '489 device, the live-fire barrel of the pistol is replaced with a modified short barrel to which an inner sleeve is threadably attached. An outer sleeve is also provided to receive the inner sleeve in a telescopic arrangement. A barrel anchor is secured to the pistol frame and a spring retention rod projects from the barrel anchor to receive a shortened recoil spring.
The aforementioned Teague '489 device is subject to several disadvantages which limit its usefulness. Most significant of these disadvantages is that the Teaque '489 device results in an obvious alteration in the outward appearance of the firearm, by the creation of an uncharacteristic muzzle signature and the corruption of manifest design elements by the introduction of components not indigenous to the design of live-fire automatic pistols.
Accordingly, the present invention is directed to a superior, highly efficient, comparatively simple, cost effect pistol adaptation which produces reliable, repetitive blank-fire capability. While incorporating a bore-occluding restrictor of appropriate geometries to generate back pressure within the firearm in a manner well known in the art, the novel elements of blank-fire modification of the present invention accomplish highly reliable, repetitive operation without visible alteration to the firearm, thus importing an exceptional degree of verisimilitude.